Set reference and previous version to 3.1.0

Author: Kordyjan

project/Build.scala

@@ -58,7 +58,7 @@ object DottyJSPlugin extends AutoPlugin {
 }
 
 object Build {
-  val referenceVersion = "3.1.0-RC1"
+  val referenceVersion = "3.1.0"
 
   val baseVersion = "3.1.1-RC1"
 
@@ -76,7 +76,7 @@ object Build {
    *  set to 3.1.3. If it is going to be 3.1.0, it must be set to the latest
    *  3.0.x release.
    */
-  val previousDottyVersion = "3.1.0-RC3"
+  val previousDottyVersion = "3.1.0"
 
   object CompatMode {
     final val BinaryCompatible = 0